8.1-STABLE: zfs and sendfile: problem still exists

Willem Jan Withagen wjw at digiware.nl
Mon Nov 1 10:39:48 UTC 2010


On 2010-11-01 8:30, Andriy Gapon wrote:
> First and foremost, the double-caching issue for ZFS+sendfile on FreeBSD is
> still there and no resolution for this issue is on horizon.  So, you have to
> account for the fact that twice as much memory is needed for this use-case.
> Whether you plan your system, or configure it, or tune it.
>
> Second, with recent head and stable/8 ARC should not be the primary victim of
> memory pressure; ARC reclaim thread and the page daemon should cooperate in
> freeing/recycling memory.
>
> Nothing much to add.

Although this discussion started due to issues with serving files thru 
web-typish services, there are more apps that use sendfile.

For one, I noticed that I had once enabled sendfile in my Samba config.
As per this discussion I saw little advantage in keeping it that way......

But I'm open for other suggestions.

--WjW





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